Grounding circuit for backup power supply

Abstract

A grounding circuit (100) for a backup power supply is provided, the backup power supply being used to power a pitch motor (33) of a pitch system (70) in a wind turbine (10). The grounding circuit (100) includes one or more switch elements (120) configured to selectively connect the backup power supply to a charging circuit (110) based on a state of a first interface element (102). The grounding circuit (100) also includes one or more switch elements (120) configured to selectively ground the backup power supply based on a state of a second interface element (104). The grounding circuit (100) includes at least one circuit protection device (140) connected between the backup power supply and the charging circuit (110). When the backup power supply is connected to the charging circuit (110) and then grounded, the at least one circuit protection device (140) is configured to disconnect the backup power supply from the charging circuit (110).

Description

Technical Field

[0001] The present disclosure generally relates to grounding circuits for a backup power source used to power a pitch motor of a pitch system in a wind turbine during adverse conditions. Background Art

[0002] Supercapacitors can be used to power loads in a pitch drive system of a wind turbine system during adverse conditions such as a grid failure. Supercapacitors can be stored in a pitch cabinet of a wind turbine. In some cases, a user (e.g., maintenance personnel) may need to perform maintenance on supercapacitors or other components located in the cabinet. However, before a user can perform maintenance on supercapacitors or other components in the cabinet, the supercapacitors must be grounded. Summary of the invention

[0003] Aspects and advantages of the invention will be set forth in the following description, or may be obvious from the description, or may be learned through practice of the invention.

[0004] In one aspect, a grounding circuit for a backup power supply is provided, the backup power supply being used to power a pitch motor of a pitch system in a wind turbine. The grounding circuit includes one or more switch elements configured to selectively connect the backup power supply to a charging circuit based on a state of a first interface element. The grounding circuit also includes one or more switch elements configured to selectively ground the backup power supply based on a state of a second interface element. The grounding circuit includes at least one circuit protection device connected between the backup power supply and the charging circuit. When the backup power supply is connected to the charging circuit and then grounded, the at least one circuit protection device is configured to disconnect the backup power supply from the charging circuit.

[0005] In another aspect, a method for grounding an ultracapacitor configured to operate a pitch motor of a pitch system in a wind turbine is provided. The method includes receiving a first input associated with disconnecting the ultracapacitor from a charging circuit at a first interface element. In response to receiving the first input, the method includes disconnecting the ultracapacitor from the charging circuit through one or more switch elements of the grounding circuit. The method also includes receiving a second input associated with grounding the ultracapacitor at a second interface element of the grounding circuit. In response to receiving the second input, the method includes grounding the ultracapacitor through one or more switch elements of the grounding circuit.

[0006] In yet another aspect, a wind turbine is provided. The wind turbine includes a pitch system, the pitch system including one or more pitch motors. The wind turbine includes a supercapacitor configured to power the one or more pitch motors. The wind turbine includes a grounding circuit for the supercapacitor. The grounding circuit includes one or more switch elements, the switch elements configured to selectively connect the supercapacitor to the charging circuit based on the state of the first interface element. The grounding circuit also includes one or more switch elements, the switch elements configured to selectively ground the supercapacitor based on the state of the second interface element. The grounding circuit includes at least one circuit protection device connected between the supercapacitor and the charging circuit. When the supercapacitor is connected to the charging circuit and then grounded, the at least one circuit protection device is configured to disconnect the supercapacitor from the charging circuit.

[0007] Technical Solution 1. A grounding circuit (100) for a backup power supply of a pitch motor (33) of a pitch system (70) in a wind turbine (10), the grounding circuit (100) comprising:

[0008] one or more switch elements (120) configured to selectively couple the backup power source to a charging circuit (110) based on a state of the first interface element (102);

[0009] one or more switch elements (120) configured to selectively connect the backup power source to ground based on a state of the second interface element (104); and

[0010] at least one circuit protection device (140) coupled between the backup power source and the charging circuit (110),

[0011] Wherein when the backup power source is coupled to the charging circuit (110) and subsequently grounded, the at least one circuit protection device (140) is configured to disconnect the backup power source from the charging circuit (110).

[0012] Technical Solution 2. The grounding circuit (100) according to Technical Solution 1 is characterized in that, when the first interface element (102) is in a first state, the one or more switch elements (120) configured to selectively connect the backup power supply to the charging circuit (110) are moved to a closed position to connect the backup power supply to the charging circuit (110), and when the first interface element (102) is in a second state, the one or more switch elements (120) configured to selectively connect the backup power supply to the charging circuit (110) are moved to an open position to separate the backup power supply from the charging circuit (110).

[0013] Technical Solution 3. The grounding circuit (100) according to Technical Solution 1 is characterized in that, when the second interface element (104) is in a first state, it is configured to selectively move the one or more switch elements (120) for grounding the backup power supply to an open position to separate the backup power supply from the ground pole, and wherein when the second interface element (104) is in a second state, it is configured to selectively move the one or more switch elements (120) for grounding the backup power supply to a closed position to ground the backup power supply.

[0014] Technical Solution 4. The grounding circuit (100) according to Technical Solution 1 is characterized in that the grounding circuit (100) also includes a resistor (160) connected between the ground electrode and one of the switching elements (120), and the switching element is configured to selectively ground the charging circuit (110).

[0015] Technical Solution 5. The grounding circuit (100) according to Technical Solution 4 is characterized in that when the backup power supply is separated from the charging circuit (110) and then grounded, the backup power supply is discharged through the resistor (160).

[0016] Technical Solution 6. The grounding circuit (100) according to Technical Solution 1 is characterized in that the one or more switch elements (120) configured to selectively ground the backup power supply include:

[0017] A first switching element (130) grounded and connected to a first branch of the backup power supply;

[0018] a second switching element (122, 132) grounded and coupled to the first branch of the backup power source between the at least one circuit protection device (140) and the charging circuit (110); and

[0019] A third switching element (134) is grounded and coupled to the second branch of the backup power source.

[0020] Technical Solution 7. The grounding circuit (100) according to Technical Solution 6 is characterized in that the grounding circuit (100) further includes a resistor (160) connected between the first switching element (130) and the ground electrode.

[0021] Technical Solution 8. The grounding circuit (100) according to Technical Solution 7 is characterized in that when the backup power supply is separated from the charging circuit (110) and then grounded, the backup power supply is discharged through the resistor (160).

[0022] Technical Solution 9. The grounding circuit (100) according to Technical Solution 6 is characterized in that the at least one circuit protection device (140) comprises:

[0023] a first circuit protection device (140) coupled between the backup power source and the charging circuit (110); and

[0024] A second circuit protection device (142) is coupled between the backup power source and a power converter (150), the power converter (150) being configured to convert direct current (DC) power from the backup power source into alternating current (AC) power for the pitch motor (33).

[0025] Technical Solution 10. The grounding circuit (100) according to Technical Solution 9 is characterized in that the one or more switch elements (120) configured to selectively connect the backup power supply to the charging circuit (110) include:

[0026] a first switching element (130) coupled to a first branch of the backup power source; and

[0027] A second switching element (122, 132) is coupled to a second branch of the backup power source.

[0028] Technical Solution 11. The grounding circuit (100) according to Technical Solution 10 is characterized in that the at least one circuit protection device (140) comprises:

[0029] a first circuit protection device (140) coupled to a first branch of the backup power supply between the charging circuit (110) and the first switching element (130), the first switching element being configured to selectively couple the backup power supply to the charging circuit (110);

[0030] a second circuit protection device (142) coupled to a first branch of the backup power source between the power converter (150) and the first switching element (130), the first switching element being configured to selectively couple the backup power source to the charging circuit (110);

[0031] a third circuit protection device (144) coupled to a second branch of the backup power supply between the charging circuit (110) and the second switching element (122, 132), the second switching element being configured to selectively couple the backup power supply to the charging circuit (110); and

[0032] A fourth circuit protection device (146) is coupled to a second branch of the backup power supply between the power converter (150) and the second switching element (122, 132), the second switching element being configured to selectively couple the backup power supply to the charging circuit (110).

[0033] Technical Solution 12. The grounding circuit (100) according to Technical Solution 11 is characterized in that the one or more switching elements (120) configured to selectively ground the backup power supply further include a fourth switching element (136), the fourth switching element (136) being connected to a second branch of the backup power supply between the power converter (150) and the second switching element (122, 132), and the second switching element being configured to selectively connect the backup power supply to the charging circuit (110).

[0034] Technical Solution 13. The grounding circuit (100) according to Technical Solution 1 is characterized in that:

[0035] The first interface element (102) includes a switch movable between at least a first position and a second position to selectively couple the backup power source to the charging circuit (110); and

[0036] The second interface element (104) includes a switch movable between at least a first position and a second position to selectively ground the backup power source.

[0037] Technical Solution 14. The grounding circuit (100) according to Technical Solution 1 is characterized in that the first interface element (102) and the second interface element (104) are associated with a control panel (106) of the wind turbine (10).

[0038] Technical Solution 15. A method (200) for grounding a supercapacitor, wherein the supercapacitor is configured to operate a pitch motor of a pitch system in a wind turbine, the method comprising:

[0039] (202) receiving, at a first interface element of a ground circuit, a first input associated with decoupling the ultracapacitor from a charging circuit;

[0040] (204) in response to receiving the first input, disconnecting the ultracapacitor from the charging circuit via one or more switching elements of the ground circuit;

[0041] (206) receiving, at a second interface element of the ground circuit, a second input associated with grounding the ultracapacitor; and

[0042] (208) In response to receiving the second input, the ultracapacitor is grounded via one or more switching elements of the grounding circuit.

[0043] These and other features, aspects and advantages of the present invention will become better understood with reference to the following description and appended claims.The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the present invention and together with the description serve to explain the principles of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] A full and complete disclosure of the invention including the best mode thereof to those skilled in the art is set forth in the specification with reference to the accompanying drawings, in which:

[0045] Figure 1 depicts a perspective view of a wind turbine according to one embodiment of the present disclosure;

[0046] Figure 2 depicts a perspective interior view of a nacelle of a wind turbine according to one embodiment of the present disclosure;

[0047] Figure 3 A schematic diagram of an embodiment of a pitch system of a wind turbine according to the present disclosure is depicted;

[0048] Figure 4 depicts a schematic diagram of one embodiment of a main power converter of a wind turbine according to an exemplary embodiment of the present disclosure;

[0049] Figure 5 depicts a grounding circuit for a supercapacitor according to an exemplary embodiment of the present disclosure;

[0050] Figure 6 The first interface element is in the second state and the second interface element is in the first state. Figure 5 Grounding circuit;

[0051] Figure 7 FIG. 1 depicts a diagram of an exemplary embodiment of the present disclosure when the first interface element is in the second state and the second interface element is in the second state. Figure 5 Grounding circuit;

[0052] Figure 8 FIG. 1 depicts a diagram of an exemplary embodiment of the present disclosure when a first interface element is in a first state and a second interface element is in a second state. Figure 5 Grounding circuit;

[0053] Fig. 9 Depicted is another grounding circuit for a supercapacitor according to an exemplary embodiment of the present disclosure;

[0054] Fig.10FIG. 1 depicts a diagram of an exemplary embodiment of the present disclosure when a first interface element is in a second state and a second interface element is in a first state. Fig. 9 Grounding circuit;

[0055] Fig.11 FIG. 1 depicts a diagram of an exemplary embodiment of the present disclosure when the first interface element is in the second state and the second interface element is in the second state. Fig. 9 Grounding circuit;

[0056] Fig.12 FIG. 1 depicts a diagram of an exemplary embodiment of the present disclosure when a first interface element is in a first state and a second interface element is in a second state. Fig. 9 Grounding circuit;

[0057] Fig.13 Depicted is yet another grounding circuit for a supercapacitor according to an exemplary embodiment of the present disclosure;

[0058] Fig.14 The first interface element is in the second state and the second interface element is in the first state. Fig.13 Grounding circuit;

[0059] Fig.15 FIG. 1 depicts a diagram of an exemplary embodiment of the present disclosure when the first interface element is in the second state and the second interface element is in the second state. Fig.13 Grounding circuit;

[0060] Fig.16 FIG. 1 depicts a diagram of an exemplary embodiment of the present disclosure when a first interface element is in a first state and a second interface element is in a second state. Fig.13 grounding circuit; and

[0061] Fig.17 A flow chart of a method according to an exemplary embodiment of the present disclosure is depicted. DETAILED DESCRIPTION

[0062] Reference will now be made in detail to embodiments of the present invention, one or more examples of which are shown in the accompanying drawings. Each example is provided by way of illustration of the present invention without limiting the present invention. In fact, it will be clear to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the present invention. For example, a feature shown or described as a part of an embodiment can be used in conjunction with another embodiment to produce another embodiment. Therefore, it is expected that the present invention covers such modifications and variations within the scope of the appended claims and their equivalents.

[0063] Exemplary aspects of the present disclosure relate to a grounding circuit for a backup power source (e.g., a supercapacitor) that is used to power an induction motor of a pitch system in a wind turbine. The grounding circuit may include one or more switch elements (e.g., contactors) configured to selectively connect the backup power source to a charging circuit based on a state of a first interface element (e.g., a switch, a lever, a button, a control panel, etc.). For example, when the first interface element is in a first state, the one or more switch elements may be moved to a closed position to connect the backup power source to the charging circuit. When the first interface element is in a second state, the one or more switch elements are moved to an open position to disconnect the backup power source from the charging circuit.

[0064] The grounding circuit may also include one or more switch elements (e.g., contactors) configured to selectively ground the backup power supply based on a state of a second interface element (e.g., a switch, a lever, a button, a control panel, etc.). When the second interface element is in a first state, the one or more switch elements move to an open position to disconnect the backup power supply from the ground electrode. Conversely, when the second interface element is in a second state, the one or more switch elements move to a closed position to ground the supercapacitor. As will be discussed in more detail below, a user (e.g., a maintenance person) may operate the first interface element and the second interface element in a predetermined sequence to properly ground the backup power supply.

[0065] In order to operate the first interface element and the second interface element in a predetermined sequence, the first interface element must be placed in the second state before the second interface element is placed in the second state. In this way, the backup power supply can be separated from the charging circuit before being grounded. When the first interface element and the second interface element are operated in a predetermined sequence, in some embodiments, the backup power supply can be discharged through a resistor of the ground circuit. More specifically, the resistor can be grounded and connected via one or more switch elements, and the switch element is configured to selectively ground the backup power supply.

[0066] Furthermore, even if the user operates the first interface element and the second interface element out of sequence (e.g., placing the second interface element in the second state before placing the first interface element in the second state), the grounding circuit includes a circuit protection device (e.g., a fuse) coupled between the charging circuit and one or more switch elements, the switch elements being configured to selectively couple the ultracapacitor to the grounding circuit. In this manner, the current associated with grounding the backup power source must flow through the circuit protection device. In an exemplary embodiment, the circuit protection device may blow when the first interface element and the second interface element are operated out of sequence, and in the process, create an open circuit. In this manner, the circuit protection device may prevent damage to the charging circuit due to the out of sequence operation of the first interface element and the second interface element.

[0067] Various aspects of the present disclosure are discussed with reference to a grounding circuit for a backup power source (e.g., a supercapacitor) for powering a pitch system in a wind turbine. Using the disclosure provided herein, one of ordinary skill in the art will appreciate that various aspects of the present embodiments may be used with other applications without departing from the scope of the present disclosure.

[0068] Now referring to the accompanying drawings, Figure 1 A perspective view of one embodiment of a wind turbine 10 according to an exemplary aspect of the present disclosure is shown. As shown, the wind turbine 10 includes a tower 12 extending from a support surface 14, a nacelle 16 mounted on the tower 12, and a rotor 18 coupled to the nacelle 16. The rotor 18 includes a rotatable hub 20 and at least one rotor blade 22 coupled to the hub 20 and extending outwardly from the hub 20. For example, in the illustrated embodiment, the rotor 18 includes three rotor blades 22. However, in alternative embodiments, the rotor 18 may include more or less than three rotor blades 22. Each rotor blade 22 may be spaced around the hub 20 to facilitate rotating the rotor 18 so that kinetic energy can be converted from the wind into usable mechanical energy and subsequently converted into electrical energy. For example, the hub 20 may be rotatably coupled to a generator 24 ( Figure 2 ), to allow the generation of electrical energy.

[0069] View now Figure 2 , a simplified internal view of one embodiment of a nacelle 16 of a wind turbine 10 is shown. As shown, a generator 24 may be disposed within the nacelle 16. The generator 24 may be coupled to the rotor 18 of the wind turbine 10. In this way, the rotational energy generated by the rotor 18 may be converted into electrical energy. In an exemplary embodiment, the rotor 18 may include a main shaft 40, which is coupled to the hub 20 to rotate therewith. The generator 24 may then be coupled to the main shaft 40 so that the rotation of the main shaft 40 drives the generator 24. For example, in the illustrated embodiment, the generator 24 includes a generator shaft 42, which is rotatably coupled to the main shaft 40 via a gearbox 44. However, in other embodiments, it should be appreciated that the generator shaft 42 may be directly rotatably coupled to the main shaft 40. Alternatively, the generator 24 may be directly rotatably coupled to the main shaft 40.

[0070] It should be appreciated that the main shaft 40 may generally be supported within the nacelle 16 by a support frame or bedplate 46 positioned atop the wind turbine tower 12. For example, the main shaft 40 may be supported by the bedplate 46 via a pair of pillow blocks 48 mounted thereto.

[0071] like Figure 1 and 2 As shown in FIG. 1 , the wind turbine 10 may also include a turbine control system or turbine controller 26 within the nacelle 16. For example, Figure 2, the turbine controller 26 is disposed within a control cabinet 52 mounted to a portion of the nacelle 16. However, it should be appreciated that the turbine controller 26 may be disposed at any location on or in the wind turbine 10, at any location on the support surface 14, or at generally any other location. The turbine controller 26 may generally be configured to control various operating modes (e.g., startup or shutdown procedures) and / or components of the wind turbine 10.

[0072] Each rotor blade 22 may also include a pitch adjustment mechanism 32 configured to rotate each rotor blade 22 about its pitch axis 34. In addition, each pitch adjustment mechanism 32 may include a pitch drive motor 33 (e.g., any suitable electric, hydraulic, or pneumatic motor), a pitch drive gearbox 35, and a pitch drive pinion 37. In this embodiment, the pitch drive motor 33 may be coupled to the pitch drive gearbox 35 so that the pitch drive motor 33 imparts mechanical force to the pitch drive gearbox 35. Similarly, the pitch drive gearbox 35 may be coupled to the pitch drive pinion 37 to rotate therewith. The pitch drive pinion 37 may in turn be rotationally engaged with a pitch bearing 54 coupled between the hub 20 and the corresponding rotor blade 22, such that rotation of the pitch drive pinion 37 causes rotation of the pitch bearing 54. Therefore, in this embodiment, rotation of the pitch drive motor 33 drives the pitch drive gearbox 35 and the pitch drive pinion 37, thereby rotating the pitch bearing 54 and the rotor blade 22 about the pitch axis 34. Similarly, wind turbine 10 may include one or more yaw drive mechanisms 38 communicatively coupled to turbine controller 26 , with each yaw drive mechanism 38 configured to change the angle of nacelle 16 relative to the wind (eg, by engaging yaw bearing 56 of wind turbine 10 ).

[0073] In addition, the turbine controller 26 can also be controlled by a separate or integrated pitch controller 30 ( Figure 1 ) is communicatively coupled to each pitch adjustment mechanism 32 (one of which is shown) of wind turbine 10 for controlling and / or changing the pitch angle of rotor blades 22 (ie, the angle that determines the perspective of rotor blades 22 relative to wind direction 28).

[0074] In addition, if Figure 2As shown in , one or more sensors 57, 58, 59 may be provided on the wind turbine 10. More specifically, as shown, the blade sensor 57 may be constructed with one or more rotor blades 22 to monitor the rotor blades 22. In addition, as shown, a wind sensor 58 may be provided on the wind turbine 10. For example, the wind sensor 58 may be a wind vane, an anemometer, a LIDAR sensor, or other suitable sensor for measuring wind speed and / or wind direction. In addition, a pitch sensor 59 may be constructed with each of the pitch drive mechanisms 32, such as one or more supercapacitors associated with its pitch drive motor 33, which will be discussed in more detail below. Therefore, the sensors 57, 58, 59 may also communicate with the pitch controller 30 and may provide relevant information to the pitch controller 30.

[0075] View now Figure 3 , providing a wind turbine 10( Figure 1 ) is a schematic diagram of an embodiment of a pitch system 70. More specifically, as shown in the figure, the pitch system 70 includes a plurality of pitch drive mechanisms 32, namely, a pitch drive mechanism ( Figure 2 ). In addition, as shown, each of the pitch drive mechanisms 32 may be communicatively coupled to the power grid 45 and the supercapacitor 72. More specifically, as shown, the supercapacitor 72 associated with each pitch drive mechanism 32 may be stored in a cabinet 74. In some embodiments, the cabinet 74 may be an insulated container.

[0076] During normal operation of the wind turbine 10, the wind turbine 10 ( Figure 1 ) receives alternating current (AC) power from grid 45 and converts the AC power into AC power suitable for driving pitch drive motor 33 (e.g., AC motor) of each pitch drive mechanism 32. In addition, main power converter 76 may convert AC power received from grid 45 into direct current (DC) power suitable for charging ultracapacitor bank 72. In some cases (e.g., adverse grid events or grid loss), pitch drive motor 33 may be driven (e.g., powered) by ultracapacitor 72.

[0077] Figure 4An exemplary embodiment of a main power converter 76 according to an exemplary embodiment of the present disclosure is depicted. The main power converter 76 may include an AC rectifier 78 configured to receive AC power from the grid 45 at a first AC voltage and convert the first AC voltage into DC power at a first DC voltage. In addition, the AC rectifier 78 may be coupled to a power inverter 80 of the main power converter 76. More specifically, the first AC rectifier 78 may be coupled to the power inverter 80 via one or more conductors (e.g., wires). In this way, the output of the AC rectifier 78 (e.g., DC power at a first DC voltage) may be provided to the power inverter 80. As shown, the main power converter 76 may include one or more capacitors 82 (e.g., electrolytic capacitors) coupled between the output of the AC rectifier 78 and the input of the power inverter 80. In an exemplary embodiment, the one or more capacitors 82 may be configured to reduce or eliminate noise associated with the DC power provided by the AC rectifier 78 to the power inverter 80.

[0078] Power inverter 80 may be configured to convert DC power at a first DC voltage into AC power at a second AC voltage. In an exemplary embodiment, the second AC voltage may be different (e.g., greater than or less than) the first AC voltage associated with the AC power received by AC rectifier 78 from grid 45. As shown, the output (e.g., AC power at the second AC voltage) may be provided to pitch drive mechanism 32 ( Figure 4 )'s pitch drive motor 33.

[0079] The main power converter 76 may include a DC to DC power converter 84. As shown, the power converter 84 may be coupled to one or more input terminals (e.g., leads) associated with the second power inverter 80. In this manner, the power converter 84 may receive DC power at a first DC voltage. Additionally, the power converter 84 may be coupled to the ultracapacitor 72. In an exemplary embodiment, the power converter 84 may convert the DC power at the first DC voltage to DC power at a second DC voltage suitable for charging the ultracapacitor 72. It should be appreciated that the second DC voltage may be different (e.g., less than or greater than) the first DC voltage.

[0080] View now Figure 5-7 According to an exemplary embodiment, a wind turbine 10 ( Figure 1 ) in the pitch system 70( Figure 3 ) of the grounding circuit 100 of the backup power supply of the pitch motor 33. As shown in the figure, the backup power supply of the pitch motor 33 includes the above reference Figure 3 and 4 However, it should be appreciated that the backup power source may include a supercapacitor 72 configured to Figure 3 and4 ) Any suitable power source for powering the pitch motor 33 when offline.

[0081] As will be discussed in more detail below, grounding circuit 100 may operate based on the states of first interface element 102 and second interface element 104. In an exemplary embodiment, first interface element 102 and second interface element 104 may be input devices (e.g., switches, levers, touch screens, buttons, etc.) configured to transition between at least a first state or position P1 and a second state or position P2 in response to user input. More specifically, first interface element 102 and second interface element 104 may be coupled to wind turbine 10 ( Figure 1 ) is associated with a control panel 106 (e.g., an electrical panel) of the wind turbine 10 ( ). However, it should be appreciated that the first interface element 102 and the second interface element 104 may include any suitable input device. It should also be appreciated that the first interface element 102 and the second interface element 104 may be located at any location on the wind turbine 10 ( Figure 1 ) at any suitable position on the .

[0082] In an exemplary embodiment, the grounding circuit 100 includes a switch element 120 that is coupled to the first branch L1 of the ultracapacitor 72 and is configured to selectively couple the ultracapacitor 72 to the charging circuit 110 based at least in part on a state of the first interface element 102 (e.g., the first state P1 or the second state P2). More specifically, the switch element 120 can be in a closed position ( Figure 5 ) and open position ( Figure 6 ) to selectively couple the ultracapacitor 72 to a charging circuit 110, which in some embodiments is a DC / DC power converter 84 ( Figure 4 Alternatively and / or additionally, the switch element 120 may be movable between a closed position and an open position to selectively couple the ultracapacitor 72 to the wind turbine 10 ( Figure 1 ) of the power converter 150. In an exemplary embodiment, the power converter 150 may be a variable pitch system 70 ( Figure 3 ) of the secondary power converter 88 ( Figure 3 ).

[0083] When the first interface element 102 is in the first state P1, the switch element 120 moves to the closed position to connect the ultracapacitor 72 (e.g., the first branch L1) to the charging circuit 110 and the power converter 150. When the first interface element 102 is in the second state P2, the switch element 120 moves to the open position ( Figure 6) to separate the ultracapacitor 72 from the charging circuit 110 and the power converter 150. In this way, the ultracapacitor 72 can be selectively coupled to the charging circuit 110 and the power converter 150 based at least in part on the state of the first interface element 102 (e.g., the first state P1 or the second state P2).

[0084] In an exemplary embodiment, the grounding circuit 100 may include one or more switching elements configured to selectively connect the ultracapacitor 72 to the ground GND. As shown, the grounding circuit 100 may include a first switching element 130, a second switching element 132, and a third switching element 134. However, it should be appreciated that the grounding circuit 100 may include more or fewer switching elements configured to selectively connect the ultracapacitor 72 to the ground GND.

[0085] As shown, each of the first switch element 130, the second switch element 132, and the third switch element 134 can be in an open position ( Figure 5 and 6 ) and closed position ( Figure 7 and 8 ) to selectively ground the ultracapacitor 72 to GND. In an exemplary embodiment, the first switch element 130 may be grounded to GND and coupled to the first branch L1 of the ultracapacitor 72. The second switch element 132 may be grounded to GND and coupled to the first branch L1 of the ultracapacitor 72. The third switch element 134 may be coupled to the second branch L2 of the ultracapacitor 72 and to GND. As will be discussed in more detail below, each of the switch elements 130, 132, 134 may be moved from an open position to a closed position, or vice versa, based on the state of the second interface element 104 (e.g., the first state P1 or the second state P2).

[0086] When the second interface element 104 is in the first state P1 ( Figure 5 and Figure 6 ), each of the switch elements 130, 132, 134 moves to the open position ( Figure 5 and Figure 6 ) to separate the supercapacitor 72 from the ground GND. On the contrary, when the second interface element 104 is in the second state P2 ( Figure 7 and 8 ), each of the switch elements 130, 132, 134 moves to a closed position ( Figure 7 and 8 ) to ground the supercapacitor 72 to GND. In this way, the supercapacitor 72 can be selectively grounded to GND based at least in part on the state of the second interface element 104 (eg, the first state P1 or the second state P2).

[0087] When it is necessary to Figure 1 ), a user (e.g., a maintenance person) may operate the first interface element 102 and the second interface element 104 in a predetermined sequence to properly ground the supercapacitor 72. First, the user may provide an input to cause the first interface element 102 to change from the first state P1 ( Figure 5 ) to the second state P2 ( Figure 6 For example, if the first interface element is a switch, the input may include moving the switch from a first position to a second position. In response to the first interface element 102 changing from the first state P1 ( Figure 5 ) to the second state P2 ( Figure 6 ), the switch element 120 configured to selectively connect the ultracapacitor 72 to the charging circuit 110 can be switched from a closed position ( Figure 5 ) to the open position ( Figure 6 ) to separate the ultracapacitor 72 from the charging circuit 110 and the power converter 150.

[0088] Next, the user may provide an input to change the second interface element 104 from the first state P1 ( Figure 6 ) to the second position ( Figure 7 ). In response to the second interface element 104 changing from the first state P1 ( Figure 5 and 6 ) to the second state P2 ( Figure 7 ), each of the first switch element 130, the second switch element 132, and the third switch element 134 configured to selectively connect the supercapacitor 72 to the ground GND can be switched from an open position ( Figure 6 ) moves to the closed position ( Figure 7 ) to connect the super capacitor 72 to ground GND.

[0089] In some embodiments, the grounding circuit 100 may include a resistor 160 connected between the ground GND and the first switching element 130, and the first switching element 130 is configured to selectively connect the supercapacitor 72 to the ground GND. Therefore, when the supercapacitor 72 is separated from the charging circuit 110 and the power converter 150 and then connected to the ground GND, the supercapacitor 72 discharges the current I through the resistor 160 of the grounding circuit 100. In an alternative embodiment, the grounding circuit 100 may not include the resistor 160 connected between the ground GND and the first switching element 130, and the first switching element 130 is configured to selectively connect the supercapacitor 72 to the ground GND.

[0090] When the user does not manipulate the first interface element 102 and the second interface element 104 in a predetermined order, the current I discharged by the supercapacitor 72 when it is initially grounded to GND may potentially damage the charging circuit 110. In order to prevent such damage to the charging circuit 110, the grounding circuit 100 may include a circuit protection device 140 (e.g., a fuse) configured to separate the supercapacitor 72 from the charging circuit 110. In an exemplary embodiment, the circuit protection device 140 may be a fuse coupled between the supercapacitor 72 and the charging circuit 110. More specifically, the circuit protection device 140 may be coupled to the first branch L1 of the supercapacitor 72 between the charging circuit 110 and the switch element 120, and the switch element 120 is configured to selectively couple the supercapacitor 72 to the charging circuit 110. In an exemplary embodiment, when the first interface element 102 and the second interface element 104 are not operated in sequence, the circuit protection device 140 (e.g., a fuse) may be blown. In this way, the charging circuit 110 may be isolated from the current I discharged by the supercapacitor 72 when it is initially grounded to GND.

[0091] View now Figure 9-12 , a schematic diagram of another embodiment of a grounding circuit 100 is provided. Figure 9-12 The grounding circuit 100 can be connected with Figure 5-8 The grounding circuit 100 is configured in substantially the same manner. However, Figure 5-8 The grounding circuit is different from 100. Figure 9-12 The grounding circuit 100 includes a second circuit protection device 142. As shown, the second circuit protection device 142 can be connected between the supercapacitor 72 and the power converter 150. More specifically, the second circuit protection device 142 can be connected to the first branch L1 of the supercapacitor 72 between the power converter 150 and the switch element 120, and the switch element 120 is configured to selectively connect the supercapacitor 72 to the ground GND. It should be appreciated that the second circuit protection device 142 can operate in substantially the same manner as the circuit protection device 140 described above. More specifically, when the first interface element 102 and the second interface element 104 are not operated in sequence, the second circuit protection device 142 can be fused. In this way, damage to the power converter 150 caused by the first interface element 102 and the second interface element 104 not operating in sequence can be prevented.

[0092] View now Figure 13-16 , a schematic diagram of yet another embodiment of a grounding circuit 100 is provided. Figure 13-15 The grounding circuit 100 can be connected with Figure 9-12 The grounding circuit 100 is configured in substantially the same manner. However, Figure 9-12 The grounding circuit is different from 100. Figure 13-16The grounding circuit 100 may include a second switching element 122 configured to selectively connect the ultracapacitor 72 to the charging circuit 110. It should be appreciated that the second switching element 122 may be the same as that described above with reference to Figures 5 to 8 The switch element 120 (eg, the first switch element) discussed above operates in substantially the same manner. More specifically, the second switch element 122 can be moved from a closed position ( Fig. 9 ) to the open position ( Fig.10 and 11 ), or vice versa, to selectively connect the ultracapacitor 72 to the charging circuit 110 and the power converter 150.

[0093] As shown, the second switch element 122 can be connected to the second branch L2 of the supercapacitor 72. Fig.13 ), the switch elements 120, 122 move to the closed position ( Fig.13 ) to connect the two branches L1, L2 of the supercapacitor 72 to the charging circuit 110 and the power converter 150. When the first interface element 102 is in the second position ( Fig.14 ), the two switch elements 120, 122 move to the open position ( Fig.14 ) so that the two branches L1, L2 of the supercapacitor 72 are separated from the charging circuit 110 and the power converter 150.

[0094] As shown in the figure, Figure 13-16 The grounding circuit 100 may include a third circuit protection device 144 and a fourth circuit protection device 146. The third circuit protection device 144 may be coupled to the second branch L2 of the supercapacitor 72 between the charging circuit 110 and the second switch 122, and the second switch 122 is configured to selectively couple the supercapacitor 72 to the charging circuit 110 and the power converter 150. The fourth circuit protection device 146 may be coupled to the second branch L2 of the supercapacitor 72 between the power converter 150 and the second switch element 122, and the second switch element 122 is configured to selectively couple the supercapacitor 72 to the charging circuit 110 and the power converter 150.

[0095] In an exemplary embodiment, Figure 13-16 The grounding circuit 100 may include a fourth switch element 136 configured to selectively connect the ultracapacitor 72 to ground GND. It should be appreciated that the first switch element 136 may be connected to the grounding circuit 100 described above. Figure 5-8 The first switch element 130, the second switch element 132, and the third switch element 134 are operated in substantially the same manner as discussed above. More specifically, the fourth switch element 136 can be moved from an open position ( Fig.13 and 14) and closed position ( Fig.15 and 16 ) or vice versa to selectively connect the supercapacitor 72 to ground GND.

[0096] As shown, the fourth switch element 136 may be coupled to the second branch L2 of the ultracapacitor 72 and the ground GND. More specifically, the fourth switch element 136 may be coupled to the second branch L2 of the ultracapacitor 72 between the fourth circuit protection device 144 and the power converter 150. In an exemplary embodiment, the fourth switch element 136 may be moved from an open position and a closed position, or vice versa, to selectively connect the second branch L2 of the ultracapacitor 72 to the ground GND.

[0097] View now Fig.17 According to an exemplary embodiment of the present disclosure, a flow chart of a method 200 for grounding a supercapacitor used to power a pitch motor of a pitch system of a wind turbine is provided. It should be appreciated that the above reference may be used Figure 5-16 The grounding circuit discussed above implements the method 200 .

[0098] At (202), method 200 includes receiving a first input associated with disconnecting an ultracapacitor from a charging circuit at a first interface element of a ground circuit. In an exemplary embodiment, the first interface element is a switch movable between at least a first position and a second position to selectively connect the ultracapacitor to the charging circuit. When the switch is in the first position, one or more switch elements (e.g., contactors) of the ground circuit may be moved to a closed position to connect the ultracapacitor to the charging circuit. When the switch is in the second position, one or more switch elements of the ground circuit may be moved to an open position to disconnect the ultracapacitor from the charging circuit. Thus, the first input may be associated with moving the switch from the first position to the second position to disconnect the ultracapacitor from the charging circuit.

[0099] In some embodiments, a lockout calibration procedure may be implemented to disconnect the ultracapacitor from the charging circuit. For example, the switch may be locked in a first position via a locking mechanism (e.g., a padlock) that is configured to prevent the switch from moving between the first position and the second position. Thus, the user must remove (e.g., unlock) the locking mechanism in order to move the switch to the second position to disconnect the ultracapacitor from the charging circuit.

[0100] At (204), method 200 includes disconnecting the ultracapacitor from the charging circuit via one or more switching elements of the ground circuit in response to receiving the first input. In an exemplary embodiment, the one or more switching elements are movable from a closed position to an open position to disconnect the ultracapacitor from the charging circuit.

[0101] At (206), method 200 includes receiving a second input associated with grounding the supercapacitor at a second interface element. In an exemplary embodiment, the second interface element may be a switch movable between at least a first position and a second position to selectively ground the supercapacitor. When the switch is in the first position, one or more switch elements of the grounding circuit may be moved to an open position to disconnect the supercapacitor from the ground electrode. When the switch is in the second position, one or more switch elements. Thus, the second input may be associated with moving the switch from the first position to the second position to ground the supercapacitor.

[0102] At (208), method 200 includes grounding the ultracapacitor via one or more switch elements of the ground circuit. In an exemplary embodiment, the one or more switch elements may be moved from an open position to a closed position to ground the ultracapacitor. In an exemplary embodiment, the ultracapacitor may be discharged through a resistor of the ground circuit. More specifically, the resistor may be coupled between a ground electrode and one of the switch elements, the switch element being configured to selectively ground the ultracapacitor.

[0103] It should be appreciated that the amount of time required to discharge a supercapacitor may be less than the amount of time required to discharge a conventional capacitor. In this way, the amount of time a user (e.g., maintenance personnel) must wait before performing maintenance on a supercapacitor or other suitable component of a wind turbine may be reduced.

[0104] In some embodiments, the first interface element and the second interface element may be operated out of sequence. For example, user manipulation of the second interface element may occur before user manipulation of the second interface element, such that the second input at (206) is received before the first input at (202). However, as described above, the grounding circuit includes at least one circuit protection device (e.g., a fuse) configured to disconnect the supercapacitor from the charging circuit when the first interface element and the second interface element are operated out of sequence. Therefore, method 200 includes disconnecting the supercapacitor from the charging circuit via the circuit protection device of the grounding circuit when the first interface element and the second interface element are operated out of sequence such that the second input at (206) is received before the first input at (202). In this way, the circuit protection device of the grounding circuit prevents the user from operating the interface elements out of sequence.

[0105] This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any device or system, and performing any incorporated method. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they include structural elements that are not different from the written language of the claims, or if they include equivalent structural elements that are not substantially different from the written language of the claims.

Claims

1. A grounding circuit (100) for a backup power supply of a pitch motor (33) of a pitch system (70) in a wind turbine (10), the grounding circuit (100) comprising: one or more switch elements configured to selectively couple the backup power source to a charging circuit (110) based on a state of the first interface element (102); one or more switch elements configured to selectively connect the backup power source to ground based on a state of a second interface element (104); as well as at least one circuit protection device (140) coupled between the backup power source and the charging circuit (110), Wherein when the backup power source is coupled to the charging circuit (110) and subsequently grounded, the at least one circuit protection device (140) is configured to disconnect the backup power source from the charging circuit (110), wherein the backup power source comprises a supercapacitor.

2. The grounding circuit (100) according to claim 1, characterized in that: When the first interface element (102) is in a first state, the one or more switch elements configured to selectively connect the backup power supply to the charging circuit (110) are moved to a closed position to connect the backup power supply to the charging circuit (110), and when the first interface element (102) is in a second state, the one or more switch elements configured to selectively connect the backup power supply to the charging circuit (110) are moved to an open position to separate the backup power supply from the charging circuit (110).

3. The grounding circuit (100) according to claim 1, characterized in that: When the second interface element (104) is in a first state, it is configured to selectively move the one or more switch elements for grounding the backup power supply to an open position to separate the backup power supply from the ground pole, and when the second interface element (104) is in a second state, it is configured to selectively move the one or more switch elements for grounding the backup power supply to a closed position to ground the backup power supply.

4. The grounding circuit (100) according to claim 1, characterized in that: The grounding circuit (100) also includes a resistor (160) coupled between a ground electrode and one of the switching elements configured to selectively ground the charging circuit (110).

5. The grounding circuit (100) according to claim 4, characterized in that: When the backup power source is separated from the charging circuit (110) and then grounded, the backup power source is discharged through the resistor (160).

6. The grounding circuit (100) according to claim 1, characterized in that: The one or more switching elements configured to selectively connect the backup power supply to ground include: a first switching element grounded and connected to a first branch of the backup power supply; a second switching element grounded and coupled to the first branch of the backup power supply between the at least one circuit protection device (140) and the charging circuit (110); and A third switching element is grounded and coupled to the second branch of the backup power source.

7. The grounding circuit (100) according to claim 6, characterized in that: The grounding circuit (100) further includes a resistor (160) connected between the first switching element and the ground.

8. The grounding circuit (100) according to claim 7, characterized in that: When the backup power source is separated from the charging circuit (110) and then grounded, the backup power source is discharged through the resistor (160).

9. The grounding circuit (100) according to claim 6, characterized in that: The at least one circuit protection device (140) comprises: a first circuit protection device (140) coupled between the backup power source and the charging circuit (110); and A second circuit protection device (142) is coupled between the backup power source and a power converter (150), the power converter (150) being configured to convert direct current (DC) power from the backup power source into alternating current (AC) power for the pitch motor (33).

10. The grounding circuit (100) according to claim 9, characterized in that: The one or more switching elements configured to selectively couple the backup power source to the charging circuit (110) include: a first switching element coupled to a first branch of the backup power source; and A second switching element is coupled to a second branch of the backup power source.

11. The grounding circuit (100) according to claim 10, characterized in that: The at least one circuit protection device (140) comprises: a first circuit protection device (140) coupled to a first branch of the backup power supply between the charging circuit (110) and the first switching element, the first switching element being configured to selectively couple the backup power supply to the charging circuit (110); a second circuit protection device (142) coupled to a first branch of the backup power source between the power converter (150) and the first switching element, the first switching element being configured to selectively couple the backup power source to the charging circuit (110); a third circuit protection device (144) coupled to a second branch of the backup power supply between the charging circuit (110) and the second switching element, the second switching element being configured to selectively couple the backup power supply to the charging circuit (110); and A fourth circuit protection device (146) is coupled to a second branch of the backup power source between the power converter (150) and the second switching element, the second switching element being configured to selectively couple the backup power source to the charging circuit (110).

12. The grounding circuit (100) according to claim 11, characterized in that: The one or more switching elements configured to selectively ground the backup power supply also include a fourth switching element connected to a second branch of the backup power supply between the power converter (150) and the second switching element, and the second switching element is configured to selectively connect the backup power supply to the charging circuit (110).

13. The grounding circuit (100) according to claim 1, characterized in that: The first interface element (102) includes a switch movable between at least a first position and a second position to selectively couple the backup power source to the charging circuit (110); and The second interface element (104) includes a switch movable between at least a first position and a second position to selectively ground the backup power source.

14. The grounding circuit (100) according to claim 1, characterized in that: The first interface element (102) and the second interface element (104) are associated with a control panel (106) of the wind turbine (10).

15. A method (200) of grounding a supercapacitor configured to operate a pitch motor of a pitch system in a wind turbine, the method comprising: (202) receiving, at a first interface element of a ground circuit, a first input associated with decoupling the ultracapacitor from a charging circuit; (204) in response to receiving the first input, disconnecting the ultracapacitor from the charging circuit via one or more switching elements of the ground circuit; (206) receiving, at a second interface element of the ground circuit, a second input associated with grounding the ultracapacitor; as well as (208) in response to receiving the second input, connecting the ultracapacitor to ground via one or more switching elements of the grounding circuit; wherein the grounding circuit further comprises at least one circuit protection device (140) connected between the supercapacitor and the charging circuit; Wherein when the supercapacitor is coupled to the charging circuit and subsequently grounded, the at least one circuit protection device (140) is configured to disconnect the supercapacitor from the charging circuit.

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